Incident Overview
During a pilot evaluation for a prospective employer, the left-seat pilot was instructed to perform an autorotation. The right-seat passenger, who was a pilot-rated individual and the potential employer, observed the maneuver.
Autorotation and Needle Split
As the pilot initiated the autorotation, he observed a split between the rotor and engine tachometer needles, with the engine tachometer reading 0 RPM. Believing the engine had failed, the pilot maintained rotor RPM within the green arc. The right-seat passenger commented on the significant needle split.
Landing and Damage
The pilot flared the helicopter at an estimated 40 feet above ground level and attempted to cushion the landing. However, the helicopter touched down hard, resulting in substantial damage to the horizontal airframe tube cross-member.
Post-Accident Examination
During an interview with FAA Aviation Safety Inspectors, the pilot reported that he could not hear the engine due to wearing a noise-canceling headset. The subsequent examination of the helicopter revealed that the throttle linkage functioned normally. All spark plugs were removed and showed indications of normal combustion. A fuel sample taken from the sump valve showed no evidence of water or particulate contamination. The FAA inspector concluded that the wreckage examination failed to identify any discrepancy or malfunction of the airframe or its components that would have contributed to the incident.